Beam trammel and calipers.



'PATENTBD mic. a,- 1903 .R. A. WILSON. BEAM TRAMMEL AND UALIPERS.

APPLICATION FILED MAY 14, 1903.

NO MODEL.

as co. wuorapfum, WASHINGTON u. c.

' UNITED STATES Patented December 8, 1903;?

PATENT OFFICE.

BEAM TRAMMEL AND CALlPERS.

SPECIFICATION forming part of Letters Patent No. 746,221, dated December8, 1903.

Application filed May 14, 1903. Serial No. 157,079. (No model.) I

To all whom it may concern.

Be it known that I, ROBERT A. WILSON, a citizen of the United States,and a resident of Watertown, in the county of Middlesex and StateofMassachusetts, have invented an Improvement in Beam Trammels andCalipers, of which the following description, in connection with theaccompanying drawings, is a specification, like letters on the drawingsrepresenting like parts.

This invention relates to trammels or beamcompasses, and has for one ofits objects to provide a novel device of this character which may beused both as a pair of calipers and as compasses and for another objectto provide a novel construction by means of which a very fine adjustmentof the legs of the compasses or calipers may be effected.

The device comprises the usual beam, upon which are adjustably mountedtwo heads. Each head carries a bar forming one of the legs of thecalipers or compasses, as the case may be. These bars or legs, as usualin this class of devices, extend transversely to the beam, and in myimproved construction oneof them is pivoted to the head, so that theends thereof may be swung toward and from the other bar orleg. Suitableadjusting devices areprovided for thus swinging the leg and for lookingit in its desired position. With this construction a general or roughadj ustment of the calipers or compasses may be obtained by adjustingthe heads longitudi nally upon the beam relative to each other and thefine and final adjustment'seoured by swinging or turning one of the legsupon its My invention also relates to a novel way of adjustably securingthe legs to the head.

In the drawings, Figure 1 is a view of my improved device, part of thebeam being broken out. Fig. 2 is a' section on the line a: m, Fig. 1.Fig. 3 is a plan view of one of the heads with the cap of the adjusting-cam removed. Fig. 4: is a section on the line y y, Fig. 3. Fig. 5is a section on the line .2 z, Fig. l.

3 designates the beam, which may be of any length desired, and tdesignates suitable heads which are slidably mounted upon the beam, andeach of which carries a bar forming one leg of the calipers orcompasses, as

hereinafter described. I have herein shown the heads as having two sides5' and 6, between which the beam 3 is received, said sides being open at7, so that difierent depths of beam may be employed, for it will heobvi-- ous that where the beam is a very long one it will be necessaryto make it comparatively. deep in order to give it sufficient strength.The sides 5 and 6 are shown as having the shoulders 8, which engageshoulders 9 on the beam, and the heads are held .in any desired adjustedposition by the set-screws 10, which are illustrated as hearing againstclamping- 05 plates 11. p

12 designates the bars which form the legs of the calipers or compasses,and said legs are each branched at one end and the branches bentoutwardly, as at 13, to form caliperpoints. The other end of each of thelegs is constructed to have removably secured there-' to either ametallic. or centering pointl t or a, pencil 15, as desired. Preferablythese legs 12 are made tubular, in which case the As herein forinofasleeve through which the leg passes. The legis clamped to the holder bymeans of a clamping-screw 16', which extends transversely through theholder, preferably through lugs 17 thereon, and situated at one side ofthe leg, as shown in Fig. 4. The clam ping-screw has a head 18, providedwith a curved surface 19; shaped to lit the curve of the leg 12, andcooperates with aclampingnut 20. When the nut 20 is tightened, thecurved surface 19 of the hea'dis drawn'against the leg 12 and the latterconsequently clamped in position. This construction permits each leg 12to be adjusted transversely of the beam and securely clamped in anyadjusted position. v v v The ordinary adjustment of the legs of thecalipers or compasses is efiected by sliding theheads back and forth onthe beam in the usual way. In order to obtain a finer adjustmentthan ispossible by adjusting the heads, I have so arranged one or both ofthe1egs 12 that it or they may be turnedto swing the ends thereof injthedirection of the length of the beam. For this purpose the holder 15 ispivoted to the side of the corresponding head. In the form of myinvention herein illustrated the holder has an arm 22, extendinglaterally therefrom, through which a pivotal screw 23 passes into thehead, and on the opposite side of the holder is another arm 24, having aslot 25, in which operates an adjusting-cam 26. This cam is shown asmounted to turn about a pivotal stud 27 and is provided with a suitableknurled head 28 for operating it. The end of the stud projects throughthe head and has aclamping-nut 29 thereon,by means of which the cam maybe locked in any adjusted position. With this construction it will beseen that by turning the cam 26 in one direction or the other the pointof the corresponding leg may be swung toward and from the other leg, andbecause of the short distance of the cam from the pivotal screw 23relative to the distance of the point orend of the leg from said screw avery slight turning movement of the cam will result in considerableadjustment of the leg.

I have herein shown the cam 26 as circular and have obtained thenecessary throw by pivoting it eccentrically, as best seen in Fig. 3. Iprefer this construction, because in any position of the cam it justfills the slot 25, and thereby prevents any backlash or loose play. Whenthe cam is clamped in its adjusted position, therefore, thecorresponding leg 12 is firmly held from movement in either direction.In order to take up any wear that may occur between the cam 26 and thewalls of the slot, I have made the two sides of said slot adjustablerelative to each other. As herein illustrated, the arm 24 is splitlongitudinally and the two parts adjusted to vary the width of the slotby means of a screw 36. I have herein illustrated both of the legs 12 asbeing thus adjustably mounted upon their corresponding heads; but myinvention would not be departed from if one of the legs was rigidlysecured to its head, as in many cases sufficient adjustment could beobtained by making one of the legs so pivoted.

While I have herein illustrated one particular way in which the legs 12may be adjustably secured to their heads, I do not wish to be limited tothis precise construction, as various changes may be made in theconstruction of the device without departing from the spirit of theinvention as expressed in the appended claims.

Having described my invention, what I claim as new, and desire to secureby Letters Patent, is-

1. In a device of the class described, a beam, two heads slidablymounted thereon, a legholder secured to the side of each head, one ofsaid leg-holders being pivoted to its head, a leg adj ustably mounted ineach leg-holder, and means to adjust the pivoted leg-holder,

whereby the ends of the corresponding leg may be adjusted longitudinallyof the beam.

2. In adevice of the class described, abeam, two heads slidably mountedthereon, a legholding sleeve for each head, a leg adjustably mounted ineach holding-sleeve, each holding-sleeve having one arm extendinglaterally therefrom which is pivoted to the head, and a second armextending from the opp0- site side thereof and provided with a slot, andan adjusting-cam operating in said slot.

3. In a device of the class described, a beam, two heads thereon eachadjustable longitudinally of the beam, a leg-holding sleeve secured tothe side of each head, a leg adjustably carried by each sleeve, eachsleeve completely surrounding the corresponding leg and being enlargedat one side to form a boss, a clamp-screw passing through each boss in adirection transverse to that of the leg and having a head thereon toengage the side of the leg, the shank of each screw being separated fromand out of contact with the corresponding leg, and a clamping-nut oneach screw.

4. In a device of the class described, abeam, two heads slidably mountedthereon, a legholding sleeve pivoted to one of said heads at one side ofthe leg, a leg adjustably supported in said sleeve, means to hold saidsleeve in any adjusted position, and a second leg secured to the otherhead.

5. In a device of the class described, a beam, two heads slidablymounted thereon, a legholder carried by each head, a leg in each holder,one of said holders having rigid therewith a laterally-extending armwhich is pivoted to the corresponding head, and means to turn saidholder about said pivot.

6. In a device of the class described, abeam, two heads slidably mountedthereon, a legholder secured to each head, a leg in each holder, one ofsaid 1eg-holders having an arm extending laterally therefrom which ispivoted to the head, and a second arm extending from the opposite sidethereof, and adjusting means coacting with said second arm to turn saidholder about its pivot.

7. In a device of the class described, abeam, two heads slidably mountedthereon, a leg holder for each head, a leg adjustably mounted in eachholder, one of said holders having an arm extending laterally therefromwhich is pivoted to the head, and a second arm extending from theopposite side thereof and provided with a slot, an adjusting-camoperating in said slot, and means to vary the width of the slot tocompensate for wear.

In testimony whereof I have signed my name to this specification in thepresence of two subscribing witnesses.

ROBERT A. WILSON.

Witnesses:

FRANK C. REED, WESLEY E. MONK.

